Kurt-Kızıldoğan Aslıhan, Otur Çiğdem, Yıldırım Kubilay, Kavas Musa, Abanoz-Seçgin Büşra
Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139, Samsun, Turkey.
Department of Molecular Biology and Genetics, Ondokuz Mayıs University, 55139, Samsun, Turkey.
Appl Microbiol Biotechnol. 2023 Sep;107(17):5453-5467. doi: 10.1007/s00253-023-12655-5. Epub 2023 Jul 12.
Fungal bioremediation is a very attractive tool to cope with environmental pollution. We aimed to decipher the cadmium (Cd) response of Purpureocillium sp. CB1, isolated from polluted soil, at transcriptome level by RNA-sequencing (RNA-seq). We used 500 and 2500 mg/L of Cd concentrations at two time points (t). RNA-seq determined 620 genes that were co-expressed in all samples. The highest number of differentially expressed genes (DEGs) was obtained within the first six h of exposure to 2500 mg/L of Cd. Several genes encoding transcriptional regulators, transporters, heat shock proteins, and oxidative stress-related genes were differentially expressed under Cd stress. Remarkably, the genes that encode salicylate hydroxylase, which is involved in naphthalene biodegradation pathway, were significantly overexpressed. Utilization of diesel as the sole carbon source by CB1 even in the presence of Cd supported concomitant upregulation of hydrocarbon degradation pathway genes. Furthermore, leucinostatin-related gene expression levels increased under Cd stress. In addition, leucinostatin extracts from Cd-treated CB1 cultures showed higher antifungal activity than the control. Notably, Cd in CB1 was mainly found as bound to the cell wall, thus confirming its adsorption potential. Cd stress slightly reduced growth and led to mycelial malformation due to Cd adsorption, especially at a concentration of 2500 mg/L at t. A strong correlation was recorded between RNA-seq and reverse-transcriptase-quantitative polymerase chain reaction (RT-qPCR) data. In conclusion, the study represents the first transcriptome analysis of Purpureocillium sp. under Cd stress, providing insights into the primary targets for rational engineering to construct strains with remarkable bioremediation potency. KEY POINTS: • Upregulation of genes encoding salicylate hydroxylases under Cd stress • Maximum Cd adsorption at 500 mg/L at t as tightly bound to the cell wall • Concordant bioremediation potential of CB1 on Cd and diesel.
真菌生物修复是应对环境污染的一种极具吸引力的工具。我们旨在通过RNA测序（RNA-seq）在转录组水平上解析从污染土壤中分离出的紫青霉属菌株CB1对镉（Cd）的响应。我们在两个时间点（t）使用了500和2500 mg/L的镉浓度。RNA-seq确定了在所有样本中共同表达的620个基因。在暴露于2500 mg/L镉的前6小时内获得的差异表达基因（DEG）数量最多。在镉胁迫下，几个编码转录调节因子、转运蛋白、热休克蛋白和氧化应激相关基因的基因差异表达。值得注意的是，参与萘生物降解途径的编码水杨酸羟化酶的基因显著过表达。即使在存在镉的情况下，CB1利用柴油作为唯一碳源也支持烃降解途径基因的同时上调。此外，在镉胁迫下，亮抑菌素相关基因的表达水平增加。此外，从经镉处理的CB1培养物中提取的亮抑菌素显示出比对照更高的抗真菌活性。值得注意的是，CB1中的镉主要以与细胞壁结合的形式存在，从而证实了其吸附潜力。镉胁迫略微降低了生长，并由于镉吸附导致菌丝体畸形，尤其是在t时浓度为2500 mg/L时。RNA-seq与逆转录定量聚合酶链反应（RT-qPCR）数据之间记录到很强的相关性。总之，该研究代表了紫青霉属菌株在镉胁迫下的首次转录组分析，为构建具有显著生物修复潜力的菌株的合理工程设计提供了主要靶点的见解。要点：•镉胁迫下编码水杨酸羟化酶的基因上调•在t时500 mg/L时镉的最大吸附量，紧密结合在细胞壁上•CB1对镉和柴油具有一致的生物修复潜力
